Daikin Kogyo Co., Ltd.

Daikin Industries, Ltd.

Nippon Telegraph and Telephone Public Corporation

Daiken Kogyo Co., Ltd.

Toshihiko Amano

Tsuneo Nakagawa

Shinichi Nakagawa

Mitsugu Omori

Sadaatsu Yamaguchi

Shigeru Morita

Hiroshi Inukai

Osamu Kogure

Tsuneo Fujii

Kohzoh Asano

Takayuki Deguchi

Masami Kakuchi

Kozo Asano

Hiroshi Asakawa

Masayoshi Tatemoto

Kiyohiko Ihara

Sadatsu Yamaguchi

Process for purification of perfluorovinyl ethers

A hexafluoropropylene oxide oligomer of the formula: RfO&lsqb;CF(CF,)CF,O&rsqb;,CF(CF,)COF in which Rf is a group represented by the formula: F(CF,),&mdash; in which m is an integer of 1 to 8, or the formula: (CF,),CF(CF,)q&mdash; in which q is an integer of 0 to 6, and n is a number of 3 to 20 is heated and thermally decomposed in a solvent at a temperature of at least 100&deg; C. in the presence of a compound which generates a fluoride (F,) ion to obtain mainly the dimer, trimer and tetramer of hexafluoropropylene oxide. Thus, the valuable low molecular weight oligomers of hexafluoropropylene oxide can be obtained from high molecular weight oligomers of hexafluoropropylene oxide which have been discarded.

Process for thermal decomposition of hexafluoropropylene oxide oligomers

A fluorine-containing copolymer comprising monomeric units of:

Fluorine-containing copolymer

A resist material of positive type having a high sensitivity, a high resolving power and an excellent adhesion property to substrates, which comprises a copolymer of a fluoroalkyl acrylate having the general formula: ##STR1## wherein R.sub.1 is methyl group, ethyl group, a halogen-substituted methyl or ethyl group, a halogen atom or hydrogen atom, R.sub.2 is a bivalent hydrocarbon group having 1 to 6 carbon atoms, and R.sub.f is a fluoroalkyl group having 1 to 15 carbon atoms, with an acrylic comonomer selected from the group consisting of a glycidyl acrylate, an acrylic acid, an acrylamide and an .alpha.-cyanoacrylate.

Fluoroalkyl acrylate resist material and process for forming fine resist

A fluorine-containing copolymer comprising monomeric units of

Fluorine-containing copolymers and films thereof

Resist material and process for forming fine resist pattern

A process for preparing a tetrafluoroethylene/fluoro(alkyl vinyl ether) copolymer comprising polymerizing tetrafluoroethylene and fluoro(alkyl vinyl ether) in an aqueous suspension system which comprises a mixed medium of water and a fluorohydrocarbon or a chlorofluorohydrocarbon in a volume ratio of from 1:1 to 10:1 at a temperature of from 0.degree. to 25.degree. C. in the presence of a polymerization initiator of the formula:

Process for preparing tetrafluoroethylene/fluoro(alkyl vinyl ether)

A fluorine-containing elastomeric copolymer which comprises units of at least one fluorovinyl ether of the formula: ##STR1## wherein X is C.sub.1 -C.sub.3 perfluoroalkyl, C.sub.1 -C.sub.3 .omega.-hydroperfluoroalkyl or C.sub.1 -C.sub.3 .omega.-chloroperfluoroalkyl, Y is hydrogen, chlorine, fluorine, trifluoromethyl, difluoromethyl or chlorodifluoromethyl and n is an integer of 1 to 4 and units of at least one other fluorine-containing monomer copolymerizable therewith, the content of the fluorovinyl ether units being 15 to 50 mol %, which has excellent resistance to low temperatures.

Fluorine-containing elastomeric copolymers, and their production

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Settsu, Japan

Toshihiko Amano